The present invention relates to a coagulant for soil and/or sand and method for preventing washout using the same, and more particularly to a coagulant for soil and/or sand which is employed to prevent washout, and to a method for preventing washout of soil and/or sand using the coagulant in which the coagulant is added to the soil and/or sand at a construction site, thereby preventing washout of the soil and/or sand in a short time.
In Japan which has a lot of volcanoes, there are a lot of volcanic ash layers in which a loamy layer is a typical example. The loamy layer contains an approximately equal amount of small grains of sand, silt and clay. Therefore, the loamy layer becomes self-adhesive when highly saturated, and becomes powdery to the contrary when dry. These properties of the loamy layer are changed in accordance with regions in which the layers are located
The loamy layer which is hard does not drain very well. The loamy layer in a mountainous region is made soft by weathering. If it rains on the loamy layer, the loamy layer becomes colloidal by containing water. The loamy layer located at a slope may slide due to weight thereof, resulting in a landslide. There are a lot of landslide regions in Japan at which several barriers made of concrete are constructed.
When it is raining steadily and a surface layer at the slope contains a lot of water beyond a certain amount, the surface layer becomes colloidal, thus decreasing internal friction of the layer. Therefore, the surface layer at the slope begins to slide in a considerable thickness due to the weight thereof. Consequently a mud slide may flow over the barriers, or sweep away the barriers. In the regions where occurrences of the landslide are unexpected, roads are often buried underneath the soil and sand brought down by the landslide and it is difficult to take emergency measures to prevent the occurrence of the landslide. That is, when constructing the barriers made of cement concrete, it is time-consuming and requires many processes which includes solidifying the foundation, providing molds, supplying concrete milk into the molds, and curing the concrete for more than three days at least until the cement solidifies. Especially, in the mountainous regions, aggregates for concrete must be transported to the construction site, which is very troublesome. Further, trucks for transporting aggregates are often brought to a standstill due to slippage by mud. Therefore a basic solution to the problems has been sought for a long time.